Latest Technology for Preservation of Male Germ Cells

抄録

　Presently, many wild animals are classified as endangered species facing the critical crisis of extinction. In ex situ conservation programs, natural mating has been widely implemented in breeding programs to maintain and restore animal populations. It is essential, however, to preserve genetic diversity when reintroducing offspring produced through captive breeding into natural habitats, because loss of diversity may reduce long-term population viability and adaptability. In this context, gamete preservation, particularly sperm cryopreservation, plays a crucial role because sperm can be relatively easily collected from both live and dead individuals. Sperm have been preserved by freezing and freeze-drying, and their fertilizing ability has been maintained long-term. Moreover, reproductive technologies using preserved sperm, such as artificial insemination, in vitro fertilization and intracytoplasmic sperm injection, are indispensable to producing the next generation in conservation breeding programs. In this review, we summarize the latest technologies for male-germ-cell preservation and the application of these technologies to the production of subsequent generations in endangered species conservation.